American Defence Secretary Donald Rumsfeld has admitted he has not seen seen 'hard evidence' linking ousted Iraqi leader Saddam Hussein and Osama Bin Laden's al Qaida.

Asked to describe the connection between Hussein and al Qaida, the Pentagon chief declined to answer the question but then said: "To my knowledge, I have not seen any strong, hard evidence that links the two."

When asked what he thought was the primary reason for invading Iraq, he said it was important to remove Saddam's regime, but he acknowledged the intelligence ahead of the invasion was faulty.

"It turns out that we have not found weapons of mass destruction," he said.